Analysis of Data Recorded by a Large Prototype TPC Equipped with a Two Layer GEM System

A TPC is considered as tracking detector at a future linear collider. The LCTPC (Linear Collider TPC) collaboration has therefore constructed a prototype TPC for R&D purposes. MPGD readout structures, such as Micromegas or GEMs, are being considered for the TPC since the demands on space and momentum resolution can not be met with a traditional wire based readout. The prototype TPC is placed in a 1 Tesla magnet at DESY and tested using an electron beam.